Well for example the left island:

## Solution

To start with, you can deduce that the two tiles on the left and right must contain mines:

because there can only be two mines around the centre tile, so the left and right **2**s must each contribute one apiece to that, otherwise you end up with a contradiction. Knowing that, you can reveal the two above the centre, as we know neither mine can be up there.

Which reveals two **4**s, so we can fill in the unknown tiles around these as containing mines, and finally we now know the two bottom unrevealed tiles must be empty.